Metallocyclic Ni₄Ln₂M₂ single-molecule magnets

Area of Science:

• Coordination Chemistry
• Materials Science
• Magnetism

Background:

• Heterotrimetallic complexes offer tunable magnetic properties.
• Lanthanide ions play a crucial role in single-molecule magnet (SMM) behavior.
• Octanuclear cyclic complexes provide a platform for exploring novel magnetic phenomena.

Purpose of the Study:

• To synthesize and characterize nine new heterotrimetallic complexes.
• To investigate the crystal structure and magnetic properties of these complexes.
• To explore the potential of these complexes as single-molecule magnets.

Main Methods:

• Synthesis of heterotrimetallic complexes using [Ni(Me2valpn)] precursor.
• X-ray crystallography for crystal structure determination.
• Magnetic susceptibility measurements (χm T vs. T curves) to determine magnetic parameters.
• Dynamic magnetic investigations to assess single-molecule magnet properties.

Main Results:

• Nine octanuclear cyclic heterotrimetallic complexes of the formula {[Ni(Me2valpn)]2Ln(H2O)M(CN)6}2 were synthesized.
• Complexes 1-5 exhibit single-molecule magnet properties with varying effective energy barriers (Ueff).
• Complex 1 ([Ni4Dy2Cr2]) displayed the highest Ueff (38.9 K) among the studied octanuclear [Ni4Ln M2] systems.
• Lanthanide ions significantly influence the magnetic performance of these heterotrimetallic SMMs.
• Substitution of diamagnetic Co(iii) with paramagnetic Cr(iii) or Fe(iii) in the [Ni4Tb2 M2] system led to SMM behavior.

Conclusions:

• The trimetallic strategy is effective for constructing new 3d-4f single-molecule magnets.
• Lanthanide ions are critical in tuning the magnetic properties of these complexes.
• The synthesized complexes demonstrate potential for applications in molecular magnetism and spintronics.